Valve-gear for engines.



PATENTED JULY 17, 1906.

0. SGHWADE. VALVE GEARLFOR ENGINES.

APPLICATION FILED 17150.14, 1905.

OTTO SOHWADE, OF ERFURT, GERMANY;

VALVE-GEAR FOR ENGINES.

Specification of Letters Patent.

ratentecl July 1'7, 1806.

Application filed December 14, 1905. Serial No. 291.750.

T0 cLZZ whom, it may concern.-

Be it known that I, Or'ro SOHWADE, manufacturer, a subject of the King of Prussia, German Emperor, residing at Erfurt, in the Kingdom of Prussia and German Empire, have invented certain new and useful Improvements in or Relating to V alve-Gear for Engines, of which the following is a specification.

My invention relates to improvements in or relating to valve-gear for engines.

In my prior Letters Patent, No. 787,223, a valvegear for double steam-engines without fly-wheel is described, which is so arranged that in the interior of the valve-chest two hollow cylinders are rotatably supported, which cannot move longitudinally and which are caused to move by the valve-rods, and thus operate the parts of the valve-gear. The movement of the hollow cylinders is effected either by the valve-rods engaging, by means of worm-threads, with similar inner wormgrooves in the hollow cylinders or by the valve-rods being secured to the hollow cylinders and by the arms reciprocated by the piston-rods being provided with inner wormgrooves, with which engage corresponding worm-threads on the valve-rods. In each case the long stroke of the piston is converted into a short movement of the slide-valve, and the dimensions of the valve-gear are reduced.

The present invention relates to improve ments in the abovementioned valve-gear as regards its construction, lubrication, and application of such valve-gear to vacuum steampumps.

A construction according to this invention is illustrated, by way of example, in the accompanying drawings.

Figure 1 is a longitudinal section of a construction of the valve-gear. Fig. 2 is a plan, and Fig. 3 is a modification in cross-section.

In order to supply oil to the valve-gear parts and to the steam, the steam-inlet pipe 1" is provided at a suitable point with an inlet 4", connected to a lubricating device or to an oil-pump of any suitable construction. The steam admitted into the valve-chest takes up oil and carries it with it, so that the oil enters the interior of the cylinder e. The hollow cylinder or rotary body is provided at a suitable point either on a portion of its circumference or all round the circumference with perforations 8, through which the steam can pass, so as to fill the same and the valvechest and to pass into one or the other cylinders. The steam, mixed with oil, then lubricates the piston in the steam-cylinder.

In Fig. 1 of said prior patent, No. 787,223, it was assumed that the valve-rod is provided with outer worm-threads engaging with the corresponding inner threads of the hollow cylinder, so that the valve-rod and hollow cylinder had the same axis. If the wormthread or the guiding curve of the hollow cylinder pass through the wall of the latter or if a corresponding worm-thread or a corresponding guide curve is cut in the outer wall of the hollow or solid cylinder or if ribs are cast on instead of it, the movement of the hollow or solid cylinder e can be brought about in the same manner and the valvegear driven if the valv e-rod c is arranged outside the cylinder e, and thus the valverod 0 and the cylinder 6 no longer have the same axis. Figs. 1 and 2 show such an arrangement. Each valve-rod c engages with its outer worm-thread f with the outer wormthread or guide curve g of the cylinder e. During the reciprocation of the valve-rod c the cylinder 6 moves and operates the valve-gear. The worm-thread or the guide curve can also be formed in the wall of the cylinder 6, and an arm 90 can be secured to the valve-rod c, the said arm proj ecting through a cam-slot g and rotating the cylinder 6 when reciprocated.

Up to now it has been difficult to utilize high-speed duplex steam-pumps, for whichthis valve-gear can also be used, as vacuumpumps, since for that purpose it is necessary that the valve-gear parts should be reversed only just at the end of the stroke of the pumppiston in order that the steam-pistons should be driven to the end of their stroke, and thus should overcome the resistance of the vacuum, which is the greatest at the end of the stroke. It is impossible in high-speed vacuum-pumps to make the valve-gear, with lever and tappets, in such manner as to leave the necessary play between the separate parts, as violent shocks to the parts of the valve-gear would be caused, and they would soon get out of order. In the pump according to this invention such an idle travel between the driving and the driven valve-gear parts is brought about by the tappets or threads f having suflicient play'in the grooves or guide curves g of the rotary body e. As the parts are screw partsthat is to say, form wedge-shaped surfacesthe parts strike against the grooves or guide curves very softly on large surfaces, and as the rotary body only rotates, but does not move longitudinally, the reversing at the end of the stroke is noiseless.

Having now particularly described and ascertained the nature of my said invention and in what manner the same is to be performed, I declare that What I claim is- 1. A valve-gear for steam-engines having hollow rotatable cylinders provided With perforations arranged in the interior of the valvechest and longitudinally immovable with re spect to the latter, a valve, valve-rods in engagement with the cylinders for driving the valve, andfmeans for admitting steam and lubricant to the cylinders, substantially as described.

2. A valve-gear of the class described, including a valve-chest, hollow means rotatably supported in the interior of the valvechest and longitudinally immovable with respect thereto and provided at the outer circumference with worm guide curves, a valve, and valve-rods having worm-threads for engagement with the Worm guide curves for actuating the valve.

3. A valve-gear of the class described, having a valve-chest, a slide-valve rod having guide means, a rotary body within the valvechest and in engagement with the guide means for operating the valve, said valve-rod having movement to allow the reversal of the valve at the end of the stroke of the piston, and means for admitting steam and lubricant to the valve-chest and rotary body.

In testimony whereof I have hereunto set my hand in presence of two subscribing witnesses.

OTTO SOHWADE. Witnesses:

PAUL TCISHMANN, FRITZ ScHNELL. 

